And yes, if I am outbid and stay outbid for days, I should be free to move on and buy elsewhere, I should not have to wait till the end of the auction.

When you open an ebay account you tick a box to say you have read and will abide by their policies, terms and conditions. Once you have ticked that box you have accepted that if a bid is removed then any lower bid made by you is valid until the auction ends so the answer is that you have agreed that you will not move on and buy elsewhere unless you don't mind having more than one of an item.